After re-testing out the (hopefully) upcoming Community Pack, there's something blatantly obvious: there are huge volume gaps from one song to another.
The tracks need to be normalized. This might not be such a trivial task - USDX probably doesn't handle ReplayGain, and normalizing is a destructive process. Some songs are really low, others are over-the-top and feature a lot of clipping. The target goal should be - of course - the official songs volume, as CaptainComedy did a clean work on what was available for the first two seasons.
Optional (?) ? the instrumental tracks are also of a lower volume by nature. In the show, lyrics tend to take over the music when it comes to volume. Maybe we should normalize that as well.
I propose to simply normalize everything to 89dB.
There are a few tools for it, I stumbled over one just today. But now it's sleeping-time first. ;)